Direct observation of the effect of oxygen on developing vessels: preliminary report.

IN previous papers it has been shown that high concentrations of oxygen are able to exert on growing retinal vessels a peculiar type of constrictor action which progresses gradually to complete obliteration of the ingrowing complexes (Ashton and others, 1953, 1954). The possible factors involved in this mechanism have already been fully discussed; it is the purpose of this paper to report preliminary experiments designed to elucidate the problem further. In order to study the process of vaso-obliteration and to correlate the findings in injected retinae with events in life, we have utilized a new limbal window technique, devised by one-of us (C.C.), which permits direct observation of the living retinal vessels. To determine whether oxygen has a similar action on growing vessels in the adult animal we have investigated the effect of hyperoxia on vascularization of the rabbit cornea and rabbit ear chamber; indirect evidence for its action on vessels in the embryo has been sought in a few experiments on hens' eggs. The methods employed together with the results obtained will be reported under the appropriate headings.